Friday, July 19, 2013

Is Crabgrass making you crabby

As the temperatures soar, so does the crabgrass population.  But, remember there’s more to it than what meets the eye. Back around the end of June, fellow AOLCP Barry Draycott’s posted this cool new information about heat loving crabgrass on the NOFA AOLCP’s LinkedIn Discussion group.

“Contrary to popular belief, crabgrass does not thrive in lawns, gardens and farm fields by simply crowding out other plants. A new study in ACS' Journal of Agricultural and Food Chemistry has found that the much-despised weed actually produces its own herbicides that kill nearby plants.

The study shows that crabgrass exudes three specific chemicals from their roots which interfere with soil microbes and have negative effects on plant growth. Information like this helps us appreciate how important soil health is for the properties we manage. Adding organic matter and microbial inoculants may be another tool in combating crabgrass.

Good to know that at the root of the matter, pardon the pun, it’s soil health. Though the hot baking sun coupled with the usual suspects of low pH, low organic matter, lack of fertility and the pains of compaction always play a role.  Lawns with weak soil profiles tend to have plants with weak root zones that don’t stand a chance against the heat loving neighbor and the three chemicals hitting them below ground. 

Luckily AOLCP’s are trained experts in assessing soil health. They also follow a standard of best cultural practices, too. Let’s face it 9 times out of 10 lawns are dealing with the stress of improper mowing right about now.

Case in point the field right by my house. They let it grow tall for weeks due to the high rain and then cut it way too short. 
This resulted in die off associated with taking off too much of the blade in one cut.  The fact that it happened in this cool weather crop's least favorite season of summer, is another part of the scenario. The crabgrass just made the most of the opportunity to flourish.

Yes, we definitely need to be adding more organic matter and microbial inoculants to build up our ailing soils!  And, trained professionals also need to engage in best cultural practice to support the plants and the soil. Mowing at the height of 3 ½” or higher creates a canopy that protects the soil and the plant health during periods of seasonal stress.  Become a wiser lawn and turf professional. You will walk away knowing about new tools to do your job with new confidence this season. Plus, learn how to better convey your mission of caring for their soil’s sustainability. Register today for the July 26th OLC Lawn & Turf Course 

Look forward to seeing you there! 
Bernadette Giblin, NOFA-AOLCP DIY Coach, Organic Land Care Consultant & Founder of Safeground Organic Landcare